Make getSecondaryRenderer non-default

The ExoPlayer interface is not generally implemented and
there is no need for default methods.

PiperOrigin-RevId: 817661255

Author: tonihei

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/ExoPlayer.java

@@ -1355,9 +1355,7 @@ public ExoPlayer build() {
    */
   @UnstableApi
   @Nullable
-  default Renderer getSecondaryRenderer(int index) {
-    return null;
-  }
+  Renderer getSecondaryRenderer(int index);
 
   /**
    * Returns the track selector that this player uses, or null if track selection is not supported.

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/SimpleExoPlayer.java

@@ -1106,6 +1106,12 @@ public Renderer getRenderer(int index) {
     return player.getRenderer(index);
   }
 
+  @Override
+  public Renderer getSecondaryRenderer(int index) {
+    blockUntilConstructorFinished();
+    return player.getSecondaryRenderer(index);
+  }
+
   @Override
   public TrackSelector getTrackSelector() {
     blockUntilConstructorFinished();

libraries/test_utils/src/main/java/androidx/media3/test/utils/StubExoPlayer.java

@@ -316,6 +316,11 @@ public Renderer getRenderer(int index) {
     throw new UnsupportedOperationException();
   }
 
+  @Override
+  public Renderer getSecondaryRenderer(int index) {
+    throw new UnsupportedOperationException();
+  }
+
   @Override
   @Nullable
   public TrackSelector getTrackSelector() {